Rotary hydraulic torque converter



July 22, 1952 H. l. F. EVERNDEN 2,603,943

ROTARY HYDRAULIC TORQUE CONVERTER Filed Sept. 24, 1946 2 SHEETS-SHEET l IJuly 22, 1952 H. l. F. EVERNDEN 2,603,943

ROTARY HYDRAULIC TORQUE CONVERTER Filed Sept.4 24, 1946 2 SHEETS-SHEET 2 fnvanlr rneys Patented July 22, 1952 normar nYnRAULIC 'ronden CONVERTER Harold IvanrFrederick Evernden, Hazlewood,

Duffeld, near Derby, Englax'iol, i assignor' to Rolls-Royce Limited, Derby, England, a British Application September 24, `1946, Serial No, 698,981@ n In Great Britain Norember 1313411 Y l.i

serian 1f, public Law 69ak august s;4 1ere l Patent @rires Novel-there; 1964, 1

3 Claims.

1 This invention is for improvements in or relating toontrofme'ans for variable-SpeedV Power transmission me nisrnrs. of the kind' comprising alrvdraulic tordu verter and an epicyclic reversing-gear, witV a bralge and a clutch for contr'elling such gear.,

' Anifmpor ant ofrlect of this invention is to pro vide a'iriechanismgf the vlrind,described which hashydra ylic N controlled'brakes and clutches foi` een' M raue-ecriverter and the enivre ,e a wherein 61.11B Operating liquid 1S used'fo'r all he brakesgandclutehefs'and for op- 1t'grn tie cpnltroljwhich controls the n A f a elutch between two of the rotat- 'Q ml -Qque'gnvltf" in accom" arieewitlrthe throttle-setting of the power unit driving the rnreglranisjn and with the speed of the output-Skagit of th.y mechanismeeording to,f a featlreofthis invention the eeritrel' 'rrbrise a hydraulically 010- erated eluth which i'ssupplied 'through a hy.-Y drauliea y dperateldshift valve, a centrlifugally controlled valve, driven at a speed' proportional to olfY the output, 'shaftl of the torque converterg lthe hydraulic line supplying 'said shift valve, a spring loading for said' shift valve, an adiustable abrutrnent'fr said spring,l and means coupling sa'il abutment to the throttle-control pdalier lever ofthe power unit.

' 'Inthe'accmpanying drawings,

1 is apartsectional view showing more or less diagrammatically the application of this invntlo'n to one type ottorqueconverter, and

"Figure shows diagrammaticallyl the hydraulic c o'rrti systernior'th'e mechanism shown in Figure 1. Referring first to Figure 1, the driving or input shaft for the powerltransinission system of a motor vehicle -is indicated at 30 and it drives through a flexible coupling 3| the impeller 32 of a hydraulic torque-converter. The driven meme ber-'or turboerunerf'33 of the torqueconverter is mounted on a shait', and the reaction member 35 is mounted through a free-wheel i5 on a shaft 36 carrying a fbrake drumv3'l; a brake 33 :zo-operates with the brake drum to lock it to the casing 39. The shaft 34 aforesaid carries a member 4l] which can be engaged by a clutch QI, with the drum 31 aforesaid so as to cause them to rotate together. The shaft 36|, also carries` a sunw-heel A42 `of an epicyclic gear whereof the planets 43 and carried on a planetcarrier and'engage In the operation ofthis device; the neutral setting is obtained by disengagne kall brakes and clutches or byenga'ging eitherthe brale 3 ,8A or the clutch All so. that the reaction member is held stationary, orlocled to the turbo-,runner 35i,l and the iiuid circulates idly in the torguefeonverter; the brake 48 and clutch 41 of the epiylic train 42, 63, are also disengaged. In order to obtain a forward drive throughthe torquefconverter, the brake 3.8 is engaged soA as to hold the reaction member 3,5 againstbaclward rotation; clutch @l is also engaged so las to lool; the planet carrier 44 to the output shaft 46 to give a solid drive through the epicyclie train from the turbo-` runner 33 by way 0f; the shaft 3,4 and the looked epicyclic train to the output: shaft 46. -When a sufciently high speed hasy been attainedjtlhe brake 3 8 is released and the clutch 4i frevrlgagd..` and the clutch 41 isA maintained in engagement, A fluid coupling drive is,A therebf obtained direet from the driving shait @il t0 the Qutrut shaft@- Thereaetion mantel when the' unit is" acting as. a torquevconverterf 1S held ageii backward rotation relative to shaft 3 6 due to a free-wheel which couples it to said shaft 36j On reach-y ing unity torque-conversion ratio (and thereafter) member Y35 is permitted by the free-wheel 95 t9 rotate forwards. When elutch 44| is engaged, rnember 3j is ompelred to travel at the SDeeq'Qf the Output. lllmr- 33 @1,161 thumt func' tions continuously as a fluid Qoihiplrfis.

The reverse driveis obtained in the usual manner by engaging av-bralre i8I with the planet carrier 4.4 so. as to render the epiyfl gear trein 42443, 45 operative to transmit a drive in the reverse diretion, the Gluteh. 4l beleg 1,35 egegedt@ transmit a fluid coupling drive tothe su-wheel l2y ofthe epicvli train- The preferred arran lement. ofhydraulic control for this transmission rnehanism'illustrated in *,.E'igure 1 lis shown diagr'ammatically in Eigure 2.`

One feature of the control gear` is that the etrange from a torqueconverting drive to a hydraulic coupling'drive, caany be'rnade to take p laee automatically infaf'seordance with the relationele? between the. threitle Opening' 0f' the meer unit and the'sne'ed Qi th Qutut Shaft Whichin this particular iianple is proportional to the speed of 'thevehiclel lteterring now to Figlie 2 the ltwo brakes 33 and.' @i are: 'shown' .ldiagrammetieally and are operated resneeti'vely by'hydraulic pistons 49,' 5B which are movedupwardsy by. the application of hydraulic pressure to the. underside of each pisthe brake.` Similarly,` thel two clutches 4| and 41 are engaged by the application of fluid pressure to them when required.

The control mechanism comprises a pump 5| which is driven from the engine, so as to be operable whenever the engine is running whether a drive is being transmitted through the mechanism or not; a second pump 52 isdriven from the output shaft or a part associated therewith so as to give hydraulic pressure whenever the vehicle is in motion; the pump 5| delivers oil under pressure through a relief valve 53 to a control valve indicated generally by the reference 54, this valve comprising pistons 55, 56 operated by th drivers control lever 51 which Ycan be set in three different positions designated F, N, R indicating forward, neutral and reverse respectively. The pump 52 is similarly provided with a relief valve 58 and communicates with the casing of the control valve 54 through conduit 60, soy that a supply of pressure fluid is delivered to the said valve through the conduits 59 and 6U. The conduit 69 also provides communication through the conduit 6| with a centrifugal governor which'is illustrated diagrammatically as a rotating casing 62 driven from the output shaft at a speed proportional thereto. The pressure fluid from the pipe 6| is admitted to a valve chamber 63 in which thereis a piston valve 64 controlling the ow of liquid therethrough, and directing it either to an outlet pipe 65 or to a sump by the pipe 66. The valve is subjected to centrifugal forces and also on its upper end to the pressure of the liquid in the pipe 65, so that the pressure delivered through the pipe 65 is a function of the speed of the vehicle.

The pipe 65 supplies pressure to a cylinder 61 to operate von a piston 68 which controls a shift valve indicated -generally by the reference 69. This valve receives a supply of liquid from the control valve 54 through the pipe 10 and controls communication by the pipe 1| with the hydraulic piston 49 which controls the brake 38 and by the pipes 12, 13 with the hydraulically o-perated clutch 4|. The pipe 13 also communicates by the pipe 14 with the control valve 54. This control valve 54 also controls the admission to pipes 15, 16 which communicate with the hydraulic piston 50 controlling the brake 48; the pipe 10 from the control valve 54 also has a connection 11 leading to the hydraulically operated clutch 41.

The shift valve 69, which constitutes an important feature of this invention, is controlled as above described by the pressure-fluid delivered to it throughthe pipe 65, but is also controlled by a spring 18 which normally presses the valve against the action of the pressure on the piston 68 and theloading of this spring is variable by means of an abutment 19 which is coupled through the linkage 8|) with the drivers control pedal 8| which operates the engine throttle in the usual manner.

-When the drivers control lever 51 is in the neutral position pressure-fluid is admitted through the pipe 14, 13 to apply the clutch 4| and to close the inlet to the pipe so that the whole gear rotates freely without transmitting a drive, as above described. For a forward drive, the Vcontrol lever is moved to the position F thereby setting the valve 55, 56 in the position shown. Communication with the pipe 14 is then cut om and the pipe 19 is opened, supplying pressure-fluid to the shift valve 69 and also to the clutch 41V to cause itto be engaged. The shiftv valve 69 being in the position indicated admits the pressure-fluid by the pipe 1I to the piston 49 to apply the brake 38 and in this position aA torque-converting drive is transmitted, as above described. As the speed of the vehicle increases and hydraulic pressure is applied to the piston 98, the valve 89 moves towards the right against the action of the spring 18. For any given loading of this spring, that is to say for any given position of the throttle valve, the speed of the vehicle will increase and the pressure on the piston 68 will therefore increase until the vehicle attains a predetermined speed corresponding to the throttle opening, when the valve 69 is moved to close communication with the pipe 1| and open communication with the pipe 12. The brake 38 is thereby released and the clutch 4| is engaged, and since the clutch 41 is already engaged, a fluid-coupling drive is transmitted in the manner above described. It will be seen that the period during which the torque-conversion drive is maintained depends upon the building up of the hydraulic pressure under theV control of the governorl 62 until the pressure is suicient to overcome the spring` 18, the loading of which is determined by the opening of the engine throttle.V In other words for alarger throttle opening, the higher is the speed which must be obtained by the vehicle before the fluid coupling drive is substituted for the torque-converting drive.

The reverse drive is obtained by movement of the drivers control lever51 to the position indicated at R. This moves the control valve 55, 56 so as to open communication to the pipe 16 and admit pressure-fluid to the hydraulic piston 59 to applyv the brake 48 and simultaneously to open the pipe 14 to apply the clutch 4|', thereby giving the reverse drive as above described.

It will be seen that bythe provisionA of the two alternative main pumps 5|, 52, a supply of pressure-fluid is ensured, at all times whether the vehicle is stationary, provided the engine is running, or in motion, even with the engine stopped. It will further be appreciated that when the system is giving a fluid-coupling drive at any speed, depression of the drivers pedal 8| will operate ,through the spring 18 to readjust the shift valve 19 and give a torque-conversiondrive. It will further be noted that when the vehicle is running at a speed above that corresponding to the throttle opening and road conditions, a fluid-coupling engine drive will be maintained until a very low vehicle speed is reached when the centrifugal governor 62 willhave lowered the oil pressure operating on the piston 68 of the shift valve and the torque-converting drive will be reinstated. This s a valuable advantage in providing for braking of the vehicle by the engine.

In Figure 2 there is shown a valve, generally indicated by the reference numeral 93, which controls the admission of oil to the engine-driven pump 5| and is moved by oil under pressure from pump 52 to its closed position against spring 94. In this way when pump 52 is functioning pump 5| ceases tol pump oil, thereby avoiding the unnecessary heating of thel oil which would otherwise take place if pump 5|'continuously delivered through its associated relief valve.

I claim: y

1. The combination with a hydraulic torquetransmittercomprising a rotatable driving member, a rotatable drivenmember, a torque-reaction member, a stationary casing, an intermediate member and a one-way clutch between said torque-reaction member and said intermediate member permitting said torque-reaction member to rotate relative to said intermediate member in the same direction as said driving and driven members and preventing said torque-reaction member from rotating relative to said intermediate member in the opposite direction; of a second clutch engageable between said intermediate member and said driven member to connect said intermediate member and said driven member for rotation together regardless of the relative speeds of said intermediate member and said driven member before engagement of said clutch, means to control the operation of said second clutch, a brake between said casing and said intermediate member, and means to control the operation of said brake, said two means being interconnected so that said brake is disengaged when said second clutch is engaged and vice versa.

2. A combination according to claim 1 further comprising an input shaft to said driving member, an output shaft from said driven member, a throttle lever controlling the power transmitted to said input shaft, a speed-sensitive device, a drive connection between said speed-sensitive device and said output shaft,.an operative connection between said means to control the operation of said second clutch and said throttle lever and a second operative connection between said means to control the operation of said second clutch and said speed-sensitive device, whereby said second clutch is operated in dependence upon the setting of said throttle lever and the speed of said output shaft.

3. In combination, a power input shaft, a power output shaft; a hydraulic torque-transmitter between said shafts, said transmitter comprising a rotatable driving member, a rotatable driven member, a torque-reaction member, a, stationary casing, and intermediate member and a one-way clutch between said torque-reaction member and said intermediate member permitting said torquereaction member to rotate relative to said intermediate member in the same direction as said driving and said driven members and preventing said torque-reaction member from rotating relative to said intermediate member in the opposite direction; a hydraulically-operated clutch engageable to connect said intermediate member and said driven member for rotation together regardless of the relative speeds of said intermediate member and said driven member before engagement of said clutch; a source of hydraulic pressure; a connection between said source and said hydraulically-operated clutch; a hydraulically-operated shift-valve to control said connection; a conduit to supply hydraulic-operating pressure from said source of pressure to said shift-valve; a centrifugally-operated valve in said conduit and a drive connection between said centrifugally-operated valve and said output shaft, whereby said centrifugally-operated valve is operative to modify the hydraulic pressure acting on said shift-valve to be proportional to the speed of said out-put shaft; a spring acting on said shift-valve to oppose the hydraulic pressure; `a throttle lever controlling the power transmitted to said input shaft; and an adjustable abutment for said spring operatively connected with said throttle lever to increase the load of said spring with increase of power transmitted to said power input shaft.

HAROLD IVANYFREDERICK EVERNDEN.

REFERENCES CITED The following references are of record in the file of this patent: A

UNITED STATES PATENTS Number Name Date 1,960,765 Kchlng May 29, 1934 2,014,944 Martyrer et al Sept. 17, 1935 2,037,252 Martyrer et al Apr. 14, 1936 2,042,189 Rabe May 26, 1936 2,120,896 Koeppen June 14, 1938 2,204,872 Thompson June 18, 1940 2,221,393 Carnegie Nov. 12, 1940 2,293,358 Pollard Aug. 18, 1942 2,298,649 Russell Oct. 13, 1942 2,302,714 Pollard Nov. 24, 1942 2,316,390 Biermann Apr. 13, 1943 2,332,593 Nutt Oct. 26, 1943 2,373,122 LaBrie Apr. 10, 1945 2,397,634 Voytech Apr. 2, 1946 

